The present invention relates to a holder for thermoresponsive means; and more particularly, to a fabricated member adapted to be disposed in intimate relationship with windings of a dynamoelectric machine, and to dynamoelectric machines including a fabricated member that is especially adapted to accommodate devices of the type generally referred to as motor overload protectors.
Extensive work has been done heretofore in connection with providing dynamoelectric machine mounting arrangements for thermoresponsive devices such as overload protectors. For example, Dubberley U.S. Pat. No. 2,909,719 illustrates an approach wherein a metal strip or fin is in heat exchange contact with the casing of motor protective means such as a thermally responsive switch. The metal strip or fin of Dubberley preferably is placed between overlapping or adjacent portions of first and second motor windings. This same Dubberley patent teaches that insulation in the form of paper or other suitable thin dielectric sheet material may be provided between the metal strip or fin and winding portions adjacent thereto.
Pleiss, Jr., et al U.S. Pat. No. 3,131,322 (which issued Apr. 28, 1964) illustrates still another approach for disposing overload protector means in heat transfer relationship to the end turns of a motor winding. With this approach, an overload protector is accommodated in a pocket formed by a V-shaped piece of metal foil. The metal foil in turn, is disposed between adjacent winding portions, with a V-shaped insulator (formed e.g., of cellulose acetate, or MYLAR material), separating the metal foil and the winding portions adjacent thereto.
With subsequent development of the motor protector mounting art, it has been suggested that economies in the manufacture of motor stators could be accomplished by eliminating the metal foil pocket members used before, and rely instead upon dielectric sheet material to establish a pocket for a motor protector. In order to eliminate the requirement that the motor protector be tied in place in the pocket established therefore; it has also been suggested to provide a dielectric material that could be used to lock against a spade type terminal of such protector. This tab then could be relied upon to hold the protector in place.
One variation from the above is to include a dielectric material flap that is folded and positioned to establish a layer of dielectric material between the stator winding and the interconnected portions of windings and external conductors. This dielectric material flap is now of a size and shape to permit it to be folded back over such interconnected portions. Cord or twine may then be tied about the folded over flap. With this arrangement, the flap then also provides extra protection against pulling the lead wires loose from the stator windings.
Heretofore, means such as lacing or tying cord have been relied upon to hold external lead wires in a desired position relative to the winding turns and separate sheets of dielectric material have been used to provide the desired insulation between conductor connections and winding end turns.
I have found that the various approaches suggested by others as described above have certain shortcomings. Accordingly, I have devised a new and improved arrangement that is economical to manufacture, and yet is believed to be extremely reliable in practice. For example, in other approaches, the insulating material seems to easily crack or break at the corners of holes formed therein that receive a protector.
Accordingly, it is an object of the present invention to provide new and improved structural means whereby improved protection against tearing of such pockets is provided.
Locking tabs provided previously have not always securely locked a protector in place and, in at least some instances, the location of entry and or locking apertures have not always been precisely located so as to properly lock a protector in place. Accordingly, another object is to provide an improved protector receptacle having an improved locking flap arrangement so that the advantages of quick assembly may be obtained and yet maximum locking strength also be established and maintained.
Still another object is to provide a uniquely contoured surface that establishes an entry hole for a fabricated, dielectric material protector holder; and yet protects against breaking of the dielectric material at the corners while providing and maintaining a snug fit of a protector disposed in such hole.
Still other objects are to provide closing tabs, and reinforcing means, in a fabricated, dielectric material, protector holder.